This is a divisional of U.S. application Ser. No. 10/190,505, filed Jul. 9, 2002, now U.S. Pat. No. 7,139,428. The entire disclosure of the prior application, application Ser. No. 10/190,505 is herewith incorporated by reference.
1. Field of the Invention
The present invention relates to an image encoder, an image encoding method, a recording medium and a computer data signal embodied in a carrier wave, for encoding electronic documents in consideration of the human recognition characteristics, thereby processing the electronic documents to be easily recognized by users and to be rapidly displayed.
2. Description of the Related Art
Recently, for the sake of conservation of natural resources or for the sake of cost reduction in office, paperless processing using IT (Information Technology) is becoming popular in companies, etc. As one paperless method, there is a technique for transforming paper documents into electronic documents. An image encoder (information encoder) reads out and digitizes information of characters or figures printed on a paper document by using a scanner, and stores the read and digitized information in an internal hard disk, etc. A user specifies an electronic document stored in the image encoder and displays the specified document on a display, so that the user can view the same information as that printed on the paper document.
The image encoder generally includes a search function for searching for a predetermined electronic document from a mass of electronic documents stored therein. To effectively use the search function, a keyword for search is attached to the electronic document. Upon reception of a search instruction together with the keyword input through the keyboard, etc., the image encoder begins searching a target electronic document.
To enhance the storage performance or transmission performance of the electronic documents, the image encoder reduces the amount of data to be encoded when transforming the paper documents into electronic documents.
The image encoder may transmit and display an electronic document using a progressive technique. According to a progressive technique, a low-quality image, whose resolution, gradation and frequency bandwidth are not initially in a sufficient level, is transmitted and displayed. Subsequently, additional information is transmitted piece by piece to gradually improve the quality of the image, and then the image with the best quality can be transmitted and displayed.
If an electronic document is transmitted using a progressive technique, a terminal which is connected to the image encoder displays a poor-quality image, and displays the image which will gradually be improved in its quality. In the end, the terminal can displays the best-quality image.
However, as compared to paper documents, the above-described image encoder (electronic documents) can not easily be handled by the users. Hence, the image encoder can not widely be spread, so that the paperless processing can not widely and efficiently be performed.
In the case where the electronic document is stored in the image encoder, the user needs to affix a reference keyword (for search) to the document. The user may feel trouble to set a certain keyword, or may have some difficulty with it. In the case where an unsuitable keyword is attached to the electronic document, this document can not be searched out. For example, if a keyword of “good-looking cloth” which is a user's subjective and personal expression is attached to a predetermined electronic document, this electronic document can not searched out based on any of ordinary keywords.
Usually, when people have the newspaper or magazine in their hand, they do not read only a target article in the newspaper or magazines. First, people briefly read the newspaper, find out an interesting article in the newspaper or magazines, and read the detail of the article afterwards.
This reading manner can not be accepted for the image encoder. In the image likewise the case of paper documents. However, according to conventional image encoders, transmission or displaying of data requires a long period of time, so that users can not just freely read the plural document pages.